It is known to create different structures by assembling and interlocking flat pieces of plastic or the like. The flat pieces are provided with peripheral notches which enable the pieces to be fitted together and interlocked at right angles to each other. An arrangement of this type is shown in U.S. Pat. No. 2,984,935. This U.S. Patent discloses a plurality of disk-like elements 10 having a plurality of peripheral notches 12 and 13. A plurality of elements 10 can be connected together by positioning each pair of such elements at right angles to each other and by then inserting the notch of one element into a notch of another element.
It is a problem to maintain a facile, consistent, and reliable interlocking of these elements 10 of U.S. Pat. No. 2,984,935. The width of the peripheral notches 12 and 13 and the thickness of the material comprising each element 10 must be such that the elements can be easily interlocked and subsequently disassembled. However, once interlocked, it is desirable that the elements remain interlocked until intentionally disassembled by the user.
It heretofore has been difficult to meet the above requirements especially in view of the abusive use given to such toys by children under the age of ten. Care must be taken in the design and fabrication of the elements so that their interlocking is facile and reliable. For example, if an element is too thick, it becomes difficult for a user, such as a child, to interlock the elements. If an element is too thin, the interlocking is easy; but the parts may not reliably remain interlocked and may accidently separate.
It can thus be seen that facile and reliable interlocking can be achieved only if the parts are designed and fabricated to precise dimensions and tolerances. However, even if the desired dimensions and tolerances are acheived initially, the subsequent wear and tear on the parts as they are used changes the original design dimensions. As a result, parts which properly and reliably interlock when new, may become loose and may accidently disengage from each other as they wear.
The above discussed factors regarding the proper fit and dimensioning of parts has several associated disadvantages. First, precision in design is required so that the parts have the correct dimensions. Second, if the parts are made of plastic, close tolerances in the making of the required molds is required. Also required is the critical processing of the parts as they are fabricated. All of these factors increase considerably the cost of design and fabrication of parts having the correct dimensions.
Thus, it can be seen that it is a problem inexpensively to design and fabricate parts that have the desired interlocking characteristics.